As an information provision device for vehicle such as an in-car information system, for example, Patent Literature 1 discloses a configuration in which a portable information device (external device) and an onboard multimedia computer with a liquid crystal display (onboard device) mounted on a vehicle are connected to each other and are controllable with respect to each other. With this configuration, an external information of the vehicle that the portable information device has (audio player, navigation system, internet browser) can be displayed to a vehicle user via a display (display unit) provided on an onboard multimedia computer.